1. Field of the Invention
This invention relates to a lock assembly for a pivotal vehicle seat, and more particularly to a lock assembly for releasably locking to an automobile floor a rear seat which, when released and folded, is pivotable forwardly upward to a substantially upright position immediately behind a front seat or seats for space saving accommodation.
2. Description of the Prior Art
In recent years, particular types of automobiles, such as vans and coaches, are becoming increasingly popular because they provide a large riding space as well as a large cargo space. In these cars, the rear seat, usually bench type, is designed to be pivotally foldable behind the front seat or seats, so that a maximum cargo space is obtained when desired. Thus, it is necessary to provide a lock mechanism or mechanisms which can releasably connect the rear seat to the automobile floor.
Japanese Utility Model Application Laid-open No. 59-51628 (Laid-open: April 5, 1984; Application No.: 57-148085; Filed: Sept. 30, 1982; Applicant: TOYOTA MOTOR CORP. et al; Inventor: Hiroichi YOSHIKAWA et al) discloses a lock assembly for a forwardly pivotable automobile seat. More specifically, the lock assembly comprises a pair of base plates joined together to define an accommodating space which houses a locking mechanism. The joined base plates are fixed to the seat cushion at each side thereof. The locking mechanism includes a latch which automatically engages a striker rod on the automobile floor when the seat cushion is pivotally brought to its substantially horizontal position of use. The locking mechanism further includes a lever which is actuated to forcibly disengage the latch from the striker rod.
The prior art lock assembly has no special means for reinforcing the base plates and is not intended to withstand a large tensile force which may be applied for example at the time of an automobile collision. In other words, the base plates may deform when a large tensile force is applied thereto. Such deformation of the base plates can cause positional deviations of the movable parts (latch and lever) housed within the accommodating space of the base plates, inviting subsequent malfunction of the movable parts.
The above problem of the prior art lock assembly becomes more serious in the case of a three-passenger bench seat which provides a seat belt safety system for all of the three passengers (instead of only two), because the tensile force applied to the lock assembly at the time of an automobile collision is extremely large.